In 2009, drug overdose deaths surpassed deaths due to motor vehicle accidents in the US. Misuse and abuse of opioid analgesics, primarily obtained through the healthcare system or from friends or relative, have dominated these trends. From 1997 to 2007 the volume of opioid analgesics dispensed through pharmacies has increased more than 6-fold, and roughly paralleled the number of people dying from opioid overdoses. This damaging flood of opioid analgesics in society reflects both calls for more aggressive treatment of pain as well as the proliferation of many different opioid analgesic formulations. Healthcare payers have an opportunity to positively impact this epidemic through claims data monitoring and prescription drug policy interventions such as prior authorization (PA) and formularies. Because states independently administer their own Medicaid programs, there are opportunities to compare and contrast differing approaches to pharmacy benefit design across similar Medicaid populations. In response to RFA-CE-14-002 (Research to Prevent Prescription Drug Overdoses), the objective of this proposal is to quantify how pharmacy benefit designs in three state Medicaid programs (Oregon, Oklahoma, Colorado) impact opioid analgesic utilization, inappropriate use, abuse, and adverse health outcomes. We will achieve this through three Aims: First, we will estimate the effects of a PA policy for long-acting opioids implemented in Oklahoma. Second, we will evaluate the impact of an opioid high dose limit implemented in Oregon. For both of these aims, we will employ a quasi-experimental approach to compare utilization and overdose-related outcomes to states without opioid policies. Finally, we will link Oregon Medicaid and prescription drug monitoring program (PDMP) data to assess the frequency and characteristics of patients who circumvent Medicaid policies by paying cash for opioids. Although this aim will be largely descriptive, it represents an innovative approach that will advance our understanding of the epidemiology of cash payments for opioids among those with prescription drug benefits. Knowledge gained from this project is relevant for state Medicaid programs for at least two reasons. First, Medicaid recipients are more likely to have substance abuse disorders and are disproportionately represented among overdose deaths. Second, in the upcoming years numerous high risk populations (e.g. recently incarcerated) will gain Medicaid coverage through the Affordable Care Act expansion. It is critical that policies which promote appropriate and safe opioid analgesic use are identified.